Anti-TPO antibodies are autoantibodies that target thyroid peroxidase (TPO), an enzyme crucial for thyroid hormone synthesis. TPO is a membrane-bound hemoprotein that catalyzes the iodination of tyrosine residues and the oxidative coupling of two tyrosine residues to thyroglobulin, essential steps in thyroid hormone production.

Clinical Significance

  • Anti-TPO antibodies indicate autoimmune thyroiditis, including:
    • Hashimoto’s thyroiditis
    • Graves' disease (diffuse toxic goiter)
  • Anti-TPO antibodies contribute to thyroid cell destruction, leading to hypothyroidism or, in some cases, thyroid dysfunction.
  • Take the test at least 2 hours after the last meal.
  • Avoid smoking for 3 hours before the test.
  • Avoid physical and emotional stress for 1 hour before the test.

This test is recommended if a patient experiences:

  • Infertility
  • Menstrual irregularities
  • Skin issues (dry skin)
  • Swelling of the face, eyelids, hands, or feet
  • Hair loss and brittle nails
  • Chronic fatigue or hyperactivity
  • Unexplained weight gain or loss
  • Depression, anxiety, or nervousness
  • Cognitive issues (memory and attention problems)
  • Muscle weakness or cramps
  • Heat or cold intolerance
  • Bloating and digestive issues
  • Tachycardia (rapid heartbeat)
  • Sleep disturbances and night sweats
  • Low libido
  • Hyperprolactinemia

Interpretation of Elevated Anti-TPO Levels

Increased Anti-TPO levels may indicate:

  • Autoimmune thyroid diseases:
    • Hashimoto’s thyroiditis (most common)
    • Graves' disease (Basedow's disease, diffuse toxic goiter)
  • Postpartum thyroiditis
  • Idiopathic hypothyroidism
  • Subclinical thyroid dysfunction
  • Other autoimmune diseases:
    • Rheumatoid arthritis
    • Systemic lupus erythematosus (SLE)
    • Type 1 diabetes
    • Pernicious anemia